Question

Q2. Solve :
(a) 2(x + 4) = 12 (c) 3(n – 5) = – 21
(e) 4(2 – x) = 8

Answer 1

Explanation:

A. 2(x+4)=12

2x+8=12

2x = 12 - 8

2x = 4

x = 2

B. 4(2 - x) = 8

8 - 4x = 8

- 4x = 8 - 8

- 4x = 0

x = 0

C. 3(n - 5) = -21

3n - 15 = - 21

3n = - 21 + 15

3n = -6

n = -2

Answer 2

Answer:

a) 2(x + 4) = 12

➨ 2x + 8 = 12 (distributive property over addition)

➨ 2x = 12 - 8 (transposing 8 to the RHS)

➨ 2x = 4

➨ x = 4/2 (transposing 2 to the RHS)

➨ x = 2

(Verification:

Putting x = 2:-

• 2(2 + 4) = 12
• 4 + 8 = 12
• 12 = 12
• LHS = RHS

Hence, verified!)

c) 3(n - 5) = -21

➨ 3n - 15 = -21 (distributive property over subtraction)

➨ 3n = -21 + 15 (transposing -15 to the RHS)

➨ 3n = -6

➨ n = -6/3 (transposing 3 to the RHS)

➨ n = -2

(Verification:

Putting n = -2:-

• 3(-2 - 5) = -21
• -6 - 15 = -21
• -21 = -21
• LHS = RHS

Hence, verified!)

(e) 4(2 - x) = 8

➨ 8 - 4x = 8 (distributive property over subtraction)

➨ -4x = 8 - 8 (transposing 8 to the RHS)

➨ -4x = 0

➨ x = 0/4 (transposing -4 to the RHS)

➨ x = 0

(Verification:

Putting x = 0,

• 4(2 - 0) = 8
• 8 - 0 = 8
• 8 = 8
• LHS = RHS

Hence, verified!)

Explanation:

• Transposition is a method where numerals are to be moved to the other side to get the value of the variable.
• The sign of the number changes when we transpose a number to the opposite side. For example, -4 becomes +4 and +2 becomes -2.